Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 301529 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1029 AM EST Wed Nov 30 2016 .SYNOPSIS... Low pressure over the upper Great Lakes will track into eastern Canada tonight. An associated cold front night will push through the Mid Atlantic late tonight. High pressure will return to the region Friday and Saturday. Low pressure will track to the west of the region Sunday night. High pressure returns Monday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Have canceled the Dense Fog Advisory everywhere...visibilities have gradually improved as showers (and warm front) continue to lift northward. Though, there could still be some patchy dense fog until warm front lifts north into PA over next few hours. Warm air advection showers continue to move northward with the warm front...with the most widespread activity remaining across NE MD. Expect showers to continue to push northward through the remainder of the morning as warm front lifts north into PA. This should lead to a break in the rainfall (especially along/east of I-95)...before the next round of rainfall moves through later today. SPC currently has our area outlined in a marginal risk for severe weather (due primarily to very high shear)...with the best potential coming later this afternoon/evening as a thin line of showers (and perhaps some embedded thunder) move through. This might not be until after 6 PM for the DC/Balt metro. Though, best chance for locally stronger wind gusts would be across southern MD. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... The longwave trough axis currently over the southern Great Plains will reach the mid-Atlantic by sunrise Thursday. An associated cold front will cross the area tonight, clearing out rain. Gusty west wind up to 30 mph both Thursday and Friday with little upslope snow. Maxima mid to upper 50s in dry air advection Thursday and five or so degrees less Friday after continued cold air advection.. && .LONG TERM /SATURDAY THROUGH TUESDAY/... High pressure will reside over the east coast Saturday. With the upper level flow in a zonal pattern temperatures will be right around climo norms for the beginning of Dec - near 50. Radiational cooling will allow temps to fall to around or slightly below the freezing Saturday night. Last night the models had some differences regarding the Sunday forecast but these seem in better line today. An open short wave is expected to track to our NW while high pressure moves into the Atlantic. There`ll be a chance of rain during the afternoon in the central Shenandoah Valley..with the moisture tracking north Sunday night. We are presently forecasting mixed precipitation west of I-95...but confidence is low with regard to the frozen precip. The high moving away means that cold air will not be held to our north which is essential..especially in a marginal situation like this. Lows expected to be in the lower to mid 30s. High pressure returns for Monday. Highs near 50. Monday night lows in the lower 30s. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... Visibilities have gradually improved at all sites as clouds and rain have spread northeast across the area. IFR conds expected to prevail by afternoon due to low cigs. Additionally, some risk for gusty showers later this afternoon/evening. Isolated thunder risk this afternoon and evening, particularly southeast of DC. South winds increase by midday with gusts into the 20 kt range. Cold front crosses the area after midnight tonight with a shift to west winds. Gusts in 25 kt range Friday and Saturday with VFR conds. VFR conditions Saturday into the at least the first part of Sunday. Clouds are expected to increase Sunday night with a chance for precipitation. && .MARINE... Just like yesterday, south winds increase today. Gusty showers and isolated thunderstorms may trigger special marine warnings, particularly in this afternoon/evening. A cold front crosses the area tonight with a shift to west winds after midnight. West winds mix down through Thursday with gusts around 25 knots across the waters. SCA through Thursday for now and is likely again both Friday and Saturday. SCA level wind gusts possible Saturday. No problems foreseen Sunday. && .TIDES/COASTAL FLOODING... Southerly flow continues on the water today ahead of a cold front that will cross late tonight. Winds will generally be 15 knots gusting 20 knots which would not cause much of a surge and the forecast is for water levels to remain below action stage thresholds for the preferred high tide this afternoon and evening. However, stronger winds may mix down as showers and isolated thunderstorms cross this afternoon. A stronger surge could occur with this activity, perhaps raising levels somewhat. New moon is today. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 6 PM EST Thursday for ANZ530>543. && $$ UPDATE...MSE PRODUCTS...BAJ/WOODY!

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